| The palladium(II)-acyl complexes, trans-Pd(PPh{dollar}sb3)sb2{dollar}(Cl)(COR), were found to alternately insert ethene and carbon monoxide at ambient temperature to form trans-Pd(PPh{dollar}sb3)sb2{dollar}(Cl) ((C(O)CH{dollar}rmsb2CHsb2)sb{lcub}x{rcub}(COR)rbrack.{dollar} There was no evidence of chain termination and the new species could be isolated, redissolved, and further insertions of ethene and carbon monoxide carried out. Graft polymers with alt-{dollar}rm Csb2Hsb4{dollar}-CO blocks were synthesized by starting with polymers with palladium(II)-acyl termini.; The alternating copolymerization of functional alkenes, {dollar}rm CHsb2{lcub}={rcub}CH(CHsb2)sb{lcub}x{rcub}OH (x=2,3,4,9){dollar} and {dollar}rm CHsb2{lcub}={rcub}CH(CHsb2)sb{lcub}x{rcub}COOH (x=1,2,4,8){dollar} with carbon monoxide was achieved by using (Pd(Me-DUPHOS)(MeCN){dollar}rmsb2rbrack(BFsb4)sb2{dollar} (Me-DUPHOS: 1,2-Bis(2,5-dimethylphospholano)benzene) as the catalyst. The resultant polymers were optically active with isotactic sequences in the backbone.; The alternating copolymerization of 1,1-dimethyl allene with carbon monoxide was achieved using (Pd(PPh{dollar}rmsb3)sb2(MeCN)sb2rbrack(BFsb4)sb2{dollar} as the catalyst. In order to gain insight into the copolymerization mechanism, the stepwise successive insertions of 1,1-dimethyl allene and carbon monoxide into palladium-carbon bonds of complexes like {dollar}rm Pdlbrack(Dppp)(Me)(MeCN)rbrack(BFsb4){dollar} (Dppp: 1,3-bis(diphenylphosphino)propane), {dollar}rm Pd(PPhsb3)sb2(Me)(Cl),{dollar} and {dollar}rm Pd(PPhsb3)sb2{dollar}(C(O)-{dollar}rm Csb6Hsb4{dollar}-Me-p)(MeCN)) (BF{dollar}sb4){dollar} were studied.; Cationic palladium complexes, (L)Pd(Me)(CH(Ph)=N(R))(BF{dollar}sb4){dollar} (L: bidentate phosphines and nitrogen ligands, R: phenyl, propyl, benzyl) were synthesized and characterized. Carbon monoxide reacted with these complexes to generate the palladium-acyl complexes with coordinated imines. The imine inserted into the Pd-carbon bond to form a Pd-alkyl species and an amide bond. The oxygen of the carbonyl group was coordinated to the palladium to form a five-membered ring. The effect of the ligand on palladium on the insertion reaction was studied. Furthermore, the reactivity of different imines were investigated.; (1,5-Cyclooctadiene)Pd(Me)(Cl) with 1 equiv of a monodentate phosphine or nitrogen ligand was found to catalyze the polymerization of methyl acrylate. Extensive studies were done to gain mechanistic insights. The catalyst system was found to be highly selective towards monomers and did not react with monomers like methyl methacrylate and acrylonitrile. Copolymerizations with these monomers was also not possible. However, copolymers of norbornene and methyl acrylate were synthesized. Copolymers of these monomers had been so far inaccessible due to the different polymerization systems applicable to each of the monomers. |
